1. Field of the Invention
The present invention relates to a lamp driving device, and a backlight assembly and a liquid crystal display apparatus having the lamp driving device, and more particularly to a lamp driving device having opening detecting function, a backlight assembly and a liquid crystal display apparatus having the lamp driving device.
2. Description of the Related Art
Generally, a liquid crystal display apparatus is a passive display apparatus that uses an external light so as to display an image. Thus, the liquid crystal display apparatus includes a backlight assembly attached at a backside of the liquid crystal display apparatus.
The backlight assembly requires characters, such as a high luminance, a high efficiency, a uniformity of the luminance, a long life span, a thin thickness, a lightweight, a low cost, etc. For example, a backlight assembly for a portable computer and a monitor of a desktop PC requires especially the long life span and the high efficiency. On the contrary, a backlight assembly for a television set requires especially the high luminance. Further, the backlight assembly for the television set requires a longer life span and a higher luminance than the backlight assembly for the monitor.
In order to satisfy the requirement, a parallel driving method has been researched. In the parallel driving method, one inverter drives a plurality of lamps. In case of the parallel driving method, when one of the lamps is in trouble, a display quality is lowered and the backlight assembly may be on fire. Thus, a feedback is essential.
However, in the parallel driving method in which one inverter drives a plurality of lamps, there is only one return path for a current. Thus, even when one or more lamps are in trouble (or opened), current flows through other normal lamps. That is, the lamp (or lamps) that is in trouble may be detected.
Further, same current flows even when at least one of the lamps is abnormal, so that over current may flow through the other lamps. Thus, the life span of the lamps is reduced, and the lamps generate over heat endangering its safety.